A Steric-Hindrance-Induced Weakly Solvating Electrolyte Boosting the Cycling Performance of a Micrometer-Sized Silicon Anode

The application of micrometer-sized silicon (mSi) ischallengingdue to the severe volume change during cycling, resulting in seriouspulverization of the mSi and detachment of active materials from thecurrent collector and consequently causing a capacity loss. Here,a new LiPF6-compatible ether electrolyte is developed toenhance the cycling performance of the mSi anode. Ethylene glycoldibutyl ether (EGDE) with large steric hindrance renders PF6 (-)-rich solvation complexes in the electrolyte,which are favorable for rapidly passivating the mSi anode surfaceand forming a LiF-rich, thin, and stratified solid electrolyte interphase(SEI). As a result, the mSi anode displays a high capacity retentionof 1901 mAh g(-1) after 500 cycles and a high CE of99.92% in a medium-concentration EGDE-LiPF6-based electrolyte.This work provides an effective strategy for extending the cyclinglife of the mSi anode by designing a new LiPF6-ether electrolytesystem.